The present invention generally relates to magnetic recording and reproducing apparatuses, and more particularly to a magnetic recording and reproducing apparatus which discriminates a performance of a magnetic recording medium in order to record a signal on and reproduce a signal from the magnetic recording medium in an optimum state, and controls a signal recording process and a signal reproducing process based on the discriminated performance of the magnetic recording medium.
In a video tape recording (hereinafter simply referred to as a VTR) which records a video signal on a magnetic recording medium such as a magnetic tape, there is provided a function of discriminating the performance of the magnetic tape so that a desired video signal can be recorded on the magnetic tape in an optimum state.
As one method of discriminating the magnetic tape performance, there was a method which records a tape discriminating signal on the magnetic tape and reproduces the tape discriminating signal, before the desired video signal is actually recorded on the magnetic tape, in order to discriminate the performance and the like of the magnetic tape based on a state of the tape discriminating signal which is reproduced from the magnetic tape. A Japanese Laid-Open Patent Application No.5-314408 proposes a magnetic recording and reproducing apparatus which enables a recording operation to be started by ending the discrimination of the magnetic tape performance within a short time, and is capable of carrying out the signal recording process depending on the magnetic tape performance.
According to this proposed magnetic recording and reproducing apparatus, the tape discriminating signal, that is, a video signal, is recorded on the magnetic tape within the short time while the magnetic tape is not transported and is stationary. For example, this short time is approximately 0.5 second or, is set to a time such that no problem will be introduced from the point of view of discriminating the magnetic tape performance. The magnetic tape performance is discriminated by reproducing the recorded video signal from the magnetic tape within a predetermined time while the magnetic tape is not transported and is stationary. For example, this predetermined time is approximately 0.5 second or, is set to a time such that no problem will be introduced from the point of view of discriminating the magnetic tape performance. However, it may be regarded that, in the proposed magnetic recording and reproducing apparatus, the time required to discriminate the magnetic tape performance is not minimized technically. The Japanese Laid-Open Patent Application No.5-314408 does not show or suggest reducing the time of approximately 0.5 second when discriminating the magnetic tape performance.
On the other hand, when recording a signal on the magnetic tape, a pre-erasure is made in order to ideally reproduce the recorded signal from the magnetic tape and because of the need to prevent undesirable effects of signal components that remain recorded on the magnetic tape. However, in the proposed magnetic recording and reproducing apparatus, no mention is made regarding erasure of prerecorded signals when recording the tape discriminating signal on the magnetic tape. For this reason, the disclosure in the Japanese Laid-Open Patent Application No.5-314408 has problems from the practical point of view.